Spacetime excersice

I think this will help me understand things better, please help.
I would like to draw a spacetime diagram of our galaxy. But I would also like to plot on the diagram two young galaxies, say 400 million years old ABB (such as those seen in the HUDF), only that they must be 180 degrees apart as seen from our galaxy. As if Hubble were now pointed 180 degrees away from the published HUDF and took another picture.

Now its easy enough to draw our past light cone. And both galaxies should lie within it, close to the null asymptotes. But how do I approximate the 180 degrees in the diagram?

Also, if I now draw the light cones (future and past)of the observed galaxies themselves, should they include one another? in their future? In their past?

I tried to do it myself, but got a headacke.
Moreover, how sould such things as the accelerated expansion and possibly the inflationary era look in the diagram?